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L Bogorad

Publications and source records attributed to L Bogorad.

At least 91 records · Page 5Linked to original sources
PubMed1985

Two partially homologous adjacent light-inducible maize chloroplast genes encoding polypeptides of the P700 chlorophyll a-protein complex of photosystem I.

The maize chloroplast chromosome contains two light-inducible genes, ps1A1 and ps1A2, that code for 45% homologous polypeptides of 83.2 and 82.5 kDa designated A1 and A2, respectively. Two types of immunochemical evidence show that the upstream gene, ps1A1, codes for a P700 chlorophyll a-protein at the reaction center of photosystem I of the photosynthetic apparatus. Antibodies against a synthetic peptide with a sequence deduced from the DNA sequence of an unconserved segment of A1 react with polypeptides of P700 chlorophyll-protein (CPI) complexes of maize and pea photosystem I; antibodies prepared against barley CPI immunoprecipitate products of in vitro transcription and translation directed by cloned chloroplast DNA containing this gene. The extensive homology between maize polypeptides A1 and A2 suggests that both may be components of CPI, although CPI has been generally considered to be comprised of two molecules of a single protein of only 66 to 70 kDa. The hexapeptide Asp-Pro-Thr-Thr-Arg-Arg in A2 is also present in another chlorophyll protein, the P680 chlorophyll a-protein of photosystem II, and is partially duplicated in A1. The number and locations of histidyl residues, which have been suggested to serve in chlorophyll binding, are highly conserved between A1 and A2.

Amino Acid Sequence↗
PubMed1985

DNA supercoiling affects in vitro transcription of two maize chloroplast genes differently.

Two adjacent, divergently transcribed, developmentally regulated genes of the maize chloroplast chromosome have different superhelical density/transcriptional activation profiles when transcribed in vitro by the homologous DNA-dependent RNA polymerase. Promoter-specific transcription of the gene for the beta and epsilon subunits of coupling factor 1 (cf1BE) increases and plateaus from templates of increasing negative superhelicity, while transcription of the gene for ribulose bisphosphate carboxylase large subunit (rcL) rises and then falls. Maximal transcription from the two promoters occurs at different template negative superhelical densities and transcription of the two genes is stimulated to different degrees. The different superhelicity profiles alter the molar ratios of the two transcripts over an order of magnitude. Changes in DNA conformation represent one possible mechanism for the differential regulation of the genes.

Chloroplasts↗
PubMed1985

Maize plastid photogenes: mapping and photoregulation of transcript levels during light-induced development.

Positively photoregulated regions that show increased transcript levels upon illumination of dark-grown seedlings are scattered over approximately 19% of the maize plastid chromosome. Some photogenes, i.e., genes within these regions, are transcribed individually, whereas others that are transcribed as polycistronic mRNAs appear to be functionally organized into operons. Multiple light-induced transcripts are complementary to most photogenes; these mRNAs are not present in equimolar amounts during plastid photomorphogenesis, but particular transcripts predominate at specific stages of development. Most, but not all, photogene RNA pools reach a maximum size (after either 10, 20, or 44 h of illumination) and then fall to approximately preillumination levels. These data and other considerations argue that photogene expression control is fundamentally transcriptional and that there is more than one expression class. Transcripts of the maize plastid gene for the large subunit of ribulose bisphosphate carboxylase reach a maximum by 20 h of illumination; transcripts of the nuclear gene for the small subunit of this enzyme continue to accumulate and fall considerably later. These data suggest that the level of transcription of the latter gene in the nucleus may be regulated by events in the chloroplast.

Chloroplasts↗
PubMed1985

Phytochrome control of levels of mRNA complementary to plastid and nuclear genes of maize.

The involvement of phytochrome in the control of the levels of RNA transcribed from maize plastid and nuclear genes was examined. The effects of illumination with red light, far-red light, or red light followed by far-red light on relative amounts of RNAs complementary to maize plastid genes for the large subunit of ribulose bisphosphate carboxylase (RuBPCase); the 32-kilodalton thylakoid membrane triazine herbicide binding B protein of photosystem II; the alpha, beta, and epsilon subunits of CF(1); subunit III (proton-translocating) of CF(0); the reaction center proteins A1 and A2 of photosystem I; two other light-induced genes for membrane proteins of photosystem II (ORFs 353 and 473); and one gene for an unidentified membrane protein (UORF 443) were measured by hybridization of labeled DNA probes to samples of leaf RNA. Transcripts of two nuclear-encoded genes, the genes for the small subunit of RuBPCase and the light-harvesting chlorophyll a/b binding protein, were studied in the same way. The levels of RNA complementary to all of these light-induced genes were significantly increased within 3 to 6 hours after brief illumination with red light. The stimulatory effects of red light were largely reversed by subsequent illumination with far-red light. It is concluded that phytochrome controls increases in the levels of mRNAs complementary to certain plastid and nuclear genes in dark-grown maize seedlings.

Journal Article↗
PubMed1985

Differential expression of the ribulose bisphosphate carboxylase large subunit gene in bundle sheath and mesophyll cells of developing maize leaves is influenced by light.

We have investigated the influence of light on the mRNA of the gene for the large subunit of ribulose-1,5-bisphosphate carboxylase in mesophyll and bundle sheath cells of the C(4) plant Zea mays. The gene is transcribed in both cell types in leaves of seedlings grown in the dark. However, upon illumination, the level of mRNA declines and becomes undetectable in mesophyll cells after 72 hours. On the contrary, in bundle sheath cells the two transcripts of the same gene increase to peak after 24 hours of greening and then decrease to a steady state level. This study was made possible by the development of improved methods for the isolation of two maize leaf cell types suitable for the extraction of high quality RNAs at different developmental states, i.e. etiolated, greening and green.

Journal Article↗
PubMed1984

Chloroplast promoter driven expression of the chloramphenicol acetyl transferase gene in a cyanobacterium.

The putative promoter region of the chloroplast encoded ps2B gene (the gene encoding the 32kD herbicide binding B protein of photosystem II (1-4)) has been fused to a chloramphenicol acetyl transferase (CAT) gene that lacks its bacterial promoter and found to accurately initiate transcription from this promoter when introduced into the cyanobacterium, Anacystis nidulans R2 (or into E. coli). The chloroplast promoter-CAT fusion was introduced into the cells on a plasmid that contains plasmid replication origins for E. coli and Anacystis as well as a second antibiotic resistance marker. Cells transformed with corresponding vectors lacking the promoter region do not express CAT.

Acetyltransferases↗
PubMed1984

Single gene for the large subunit of ribulosebisphosphate carboxylase in maize yields two differentially regulated mRNAs.

A second mRNA coding for the large subunit of ribulose-1,5-bisphosphate carboxylase [3-phospho-D-glycerate carboxylase (dimerizing), EC 4.1.1.39] has been found in the plastids of maize leaves. The 5' terminus of this mRNA was shown by S1 nuclease analysis to be 238 nucleotides upstream of the previously described large subunit mRNA [McIntosh, L., Poulsen, C. & Bogorad, L. (1980) Nature (London) 288, 556-560]. The same two mRNAs were produced in a homologous in vitro transcription system using cloned plastid DNA as a template. The ratio of the two mRNAs changes during light-induced plastid development and can be altered in the in vitro system by manipulation of transcription conditions.

Base Composition↗
PubMed1984

Nucleotide sequence of a multiple-copy gene for the B protein of photosystem II of a cyanobacterium.

Chloroplast photogene 32 codes for the 32-kilodalton triazine herbicide-binding protein at the B site of electron transport in photosystem II of the photosynthetic apparatus-its product is the B protein and the gene is accordingly designated ps2B here. The cyanobacteria Anacystis nidulans R2, Fremyella diplosiphon, and Nostoc sp. MAC each contain several copies of ps2B. The sequence of one copy of ps2B from Fremyella, ps2B-1, has been determined. The longest open reading frame would code for a protein of 360 amino acids. Although the deduced amino acid sequence of ps2B-1 is highly homologous overall to that of the corresponding spinach protein [Zurawski, G., Bohnert, H. J., Whitfeld, P. R. & Bottomley, W. (1982) Proc. Natl. Acad. Sci. USA 79, 7699-7703] and, excluding neutral substitutions, the homology is 95% for an internal segment of 309 amino acids, there are a number of nonneutral amino acid substitutions. Most of the differences in net charge and polarity occur in the first 20 amino acids at the amino terminus and in the amino acid composition at the carboxyl terminus. The nucleotide sequences are 76% homologous overall. Conserved sequences resembling prokaryotic "-10" and "-35" regions are found at remarkably similar positions in the spinach and F. diplosiphon sequences although the surrounding sequences show only occasional homologies.

Journal Article↗
PubMed1983

Maize chloroplast DNA encodes a protein sequence homologous to the bacterial ribosome assembly protein S4.

A cloned restriction fragment of maize chloroplast DNA (Bam H1 fragment 5) is shown to contain an open reading frame which encodes a basic protein of 201 amino acid residues with 40-50% sequence homology to E. coli ribosomal protein S4. Based on the experimentally determined sequence homology between the highly conserved bacterial ribosomal protein L12 and its chloroplast homologue (Bartsch M., Kimura, M. and Subramanian, A.R. (1982) Proc. Natl. Acad. Sci. USA 79, 6871), we conclude that this reading frame represents the maize chloroplast S4 gene. The nucleotide sequence of a 1100 base pair DNA segment containing the putative gene is presented.

Amino Acid Sequence↗
PubMed1983

Nucleotide sequences of five maize chloroplast transfer RNA genes and their flanking regions.

Maize chloroplast tRNA genes encoding tRNA3Ser, tRNAPhe, tRNA2Thr, tRNA2Leu, and tRNAmMet, and their flanking regions have been sequenced. All five gene sequences show features commonly found in the few chloroplast tRNA genes sequenced so far; none of them encodes the 3'-terminal CCA triplet and none of them shows abnormal loop or stem lengths as seen in some genes for mammalian mitochondrial tRNAs. The 5'-flanking regions of some of these tRNA genes contain nucleotide stretches strongly homologous to -35 and -10 promoter regions of bacterial genes. Analysis of these conserved regions together with those seen in other plastid genes yields the consensus sequences ATTGANA at "-35" and TAAGAT at "-10." The 3'-flanking regions of some tRNA genes show dyad symmetries followed by a stretch of Thds. These and other regions may be involved in transcription termination or transcript processing.

Base Sequence↗
PubMed1982

The maize chloroplast genes for the beta and epsilon subunits of the photosynthetic coupling factor CF1 are fused.

We have cloned and sequenced the maize chloroplast genome fragment Eco RI e which contains the 2.2 kb transcript previously reported (Link, G. and Bogorad, L. (1980) Proc. Nat. Acad. Sci. 77 6821-6825) to lie next to the maize gene for the large subunit of ribulose bisphosphate carboxylase (LS) and to be transcribed divergently. Immunochemical and sequencing data show that the gene codes for the beta subunit of the maize chloroplast coupling factor complex (CF1). The derived amino acid sequence is highly homologous to that of the corresponding E. coli protein (Saraste et al. (1981) Nucleic Acids Res. 9 5287-5296). The last base of the codon for the terminal lysine residue of the beta subunit of CF1 is the first base of the codon for the initiating methionine of an open reading frame whose derived amino acid composition and size closely match that reported for the epsilon subunit (Binder et al. (1978) J. Biol. Chem. 253 3094-3100). The close coupling of the two genes may serve to in sure their stoichiometric production.

Base Sequence↗
PubMed1982

The anticodon of the maize chloroplast gene for tRNA Leu UAA is split by a large intron.

The maize chloroplast gene encoding tRNA Leu UAA has been sequenced. It contains a 458 base pair intron between the first and second bases of the anticodon. The tRNA is 88 nucleotides long (the 3'-terminal CCA sequence included which, however, is not encoded by the gene) and differs in only four nucleotides (modified nucleotides are not considered) from the corresponding isoacceptor from bean chloroplasts. The unusual position of the intron in this maize chloroplast tRNA gene suggests a splicing model different from that generally accepted for eukaryotic split tRNA genes.

Anticodon↗
PubMed1981

Differential transcription in vivo and in vitro of two adjacent maize chloroplast genes: The large subunit of ribulosebisphosphate carboxylase and the 2.2-kilobase gene.

The transcription of cloned maize plastid DNA sequences in vitro by maize plastid DNA-dependent RNA polymerase has been studied to expose the roles of the enzyme, polypeptide cofactors, and DNA sequences in the regulation of gene expression. The 4.35-kilobase pair BamHI fragment 9 carries the maize plastid gene for the large subunit of ribulosebisphosphate carboxylase and part of the gene for a 2.2-kilobase RNA. These two genes are separated by approximately 330 base pairs and are transcribed divergently. Transcripts of the gene for the large subunit of ribulosebisphosphate carboxylase are abundant in bundle sheath cells of maize leaves and we show here that transcripts of the 2.2-kilobase RNA gene are present in both mesophyll cells and the adjacent bundle sheath cells. In vitro, in the presence of the S factor, maize chloroplast DNA-dependent RNA polymerase produces a transcript of the gene for the large subunit of ribulose-bisphosphate carboxylase with a 5' terminus like that of the corresponding mRNA isolated from plastids, transcribes chloroplast DNA sequences of Bam fragment 9 in a chimeric plasmid in preference to the vehicle RSF 1030 and, in a ratio of 3:1, preferentially transcribes the gene for the large subunit of ribulosebisphosphate carboxylase over the 2.2-kilobase RNA gene from supercoiled chimeric plasmid DNA.

Journal Article↗
PubMed1981

Identification of the triazine receptor protein as a chloroplast gene product.

The triazine herbicides inhibit photosynthesis by blocking electron transport at the second stable electron acceptor of photosystem II. This electron transport component of chloroplast thylakoid membranes is a protein-plastoquinone complex termed "B." The polypeptide that is believed to be a component of the B complex has recently been identified as a 32- to 34-kilo-dalton polypeptide by using a photoaffinity labeling probe, azido-[(14)C]atrazine. A 34-kilodalton polypeptide of pea chloroplasts rapidly incorporates [(35)S]methionine in vivo and is also a rapidly labeled product of chloroplast-directed protein synthesis. Trypsin treatment of membranes tagged with azido-[(14)C]atrazine, [(35)S]methionine in vivo, or [(35)S]methionine in isolated intact chloroplasts results in identical, sequential alterations of the 34-kilo-dalton polypeptide to species of 32, then 18 and 16 kilodaltons. From the identical pattern of susceptibility to trypsin we conclude that the rapidly synthesized 34-kilodalton polypeptide that is a product of chloroplast-directed protein synthesis is identical to the triazine herbicide-binding protein of photosystem II. Chloroplasts of both triazine-susceptible and triazine-resistant biotypes of Amaranthus hybridus synthesize the 34-kilodalton polypeptide, but that of the resistant biotype does not bind the herbicide.

Journal Article↗
PubMed1981

Overlapping divergent genes in the maize chloroplast chromosome and in vitro transcription of the gene for tRNA.

In the presence of the S polypeptide, maize chloroplast DNA-dependent RNA polymerase preferentially transcribes sequences within the 2200-nucleotide-pair-long maize chloroplast chromosome fragment Eco [unk] from a supercoiled chimeric plasmid cloned in Escherichia coli [Jolly, S. O. & Bogorad, L. (1980) Proc. Natl. Acad. Sci. USA 77, 822-826]. Eco [unk] contains one gene for tRNA(His) and one for a 1.6-kilobase RNA that includes an open reading frame. These two genes overlap by at least a few nucleotides and are transcribed divergently from complementary DNA strands. This indicates possible transcriptional regulation of chloroplast DNA at the nucleotide level. The 5' end of tRNA(His) (G-U-G) isolated from maize chloroplasts is indistinguishable from that of the transcript produced from Eco [unk] in vitro by maize chloroplast DNA-dependent RNA polymerase. This purified system initiates RNA synthesis faithfully and exhibits preference for some chloroplast genes. Maize chloroplast DNA for tRNA(His) lacks the sequence C-C-A at its 3' terminus; it is presumably added post-transcriptionally. Maize tRNA(His) has both prokaryotic and eukaryotic features.

Journal Article↗
PubMed1981

A gene coding for tRNA is located near 5' terminus of 16S rRNA gene in Zea mays chloroplast genome.

A region of 635 base pairs preceding a gene for 16S rRNA in the Zea mays chloroplast genome has been mapped and its sequence has been determined. Screening for structural elements common to tRNAs reveals a gene coding for tRNA(Val) (GU(U) (C)) positioned 303 base pairs proximal to the 5' end of the 16S rRNA gene. Both the tRNA(Val) and the 16S rRNA are coded in the same DNA strand. The tRNA nucleotide sequence predicted from the DNA sequence meets all structural characteristics common to tRNA primary and secondary structures. In a quantitative comparison with primary structures of the 14 known tRNA(Val) species the chloroplast isoaceptor shows much higher homology with that from prokaryotic than that from eukaryotic species. Regions that Escherichia coli RNA polymerase protects from nuclease attack are observed 25 and 100 base pairs upstream of the tRNA(Val) gene and 105 base pairs upstream of the 16S rRNA gene. Within these regions are short sequences that are very similar to those in the -35 region of E. coli rrn and that may therefore represent all or parts of transcription initiation signals of the respective genes.

Journal Article↗
PubMed1981

Chloroplasts.

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Apoproteins↗